The Worst Prank
by The Demon Ledger
Summary: Sirius plans a prank on Severus Snape, and it goes terribly wrong. Based on the little bit of information given about the prank in PoZ. Rated T for a little bit of violence and some swearing.


_A/N: School ends on the 12th of June, and I'll be doing more writing then! As for now, here's a one-shot for you. I just finished PoA again, and thought this would be a fun story to write. I hope you enjoy it._

 _Don't forget to review and favorite, follow me if you're interested in seeing anything else. My next story I'm going to update should be coming soon enough, and will be for my Remus/Sirius story, Moon and Stars. Keep an eye out for that, if you enjoy this one, which will be within the same universe. After that should be an update for my long running Hunger Games story Hands and Fire, as well as my Haymitch story Poison Me, followed by an update to Love, my Hunger Games AU. After that I have an idea that sprung at me while I was falling asleep for a Harry Potter AU._

 _Anyways, get onto reading!_

 _Keep sane; ~B_

* * *

Sirius Black's face had not fallen out of its smirk since he'd run into Snape after Transfiguration. The plan he'd had in his head for months - to scare the pants of the greasy git - was finally in motion. He hadn't told any of his friends yet, of course, and he couldn't tell Remus. They'd already been fighting, and Sirius couldn't risk angering him further. But, Sirius knew someone who would definitely appreciate it. The plan was simple enough: get Snape to the Whomping Willow tomorrow night, jump out as the dog, and chase him off. He hoped, even expected, that Snape would stop sneaking around, trying to find out about Remus.

He entered the Common Room with a perfunctory 'toadstools' and immediately began looking around for James Potter, his best friend.

James, as usual, was staring at Lily Evans, a very pretty red-head in their year, from the squishy armchair beside the fire. He raised a hand towards Sirius as he began to walk towards James, then looked at him.

"What's up with you?" asked Sirius.

"I heard she went out with Longbottom." said James, brow furrowed.

"Nah," replied Sirius, flopping onto the couch, "He's with Alice Thicke. Been together since forever." James nodded.

"Then why did I hear they went out?" he asked.

"Who told you they did?"

"Wormtail."

"Well you can't trust anything he says. Highly impressionable, that one."

"Don't I know it," James sighed and shifted so he couldn't see Lily anymore. "What's up with you?" James asked now, finally scanning Sirius' face.

"I have a great, fantastic, wonderful trick to play on Snivellus," replied Sirius. He saw Lily stiffen out of the corner of his eye, but ignored her. She had no reason to care about the great slime-ball, not since what happened last year. But even still, he lowered his voice slightly. James had an eyebrow raised towards him. "I need your help."

"Yeah?" replied James, voice just as low. Sirius chanced a glance towards Lily. She'd frozen in the middle of correcting something on a fourth-years paper, staring at it unblinkingly.

"Tomorrow night, I told Snivellus to head out to the spot at the Willow. If we're lucky, we'll be able to spook him halfway do-"

"Tomorrow's the full moon!" said James. His eyes were wide, but his brow was furrowed, giving him a very deer-ish look.

Sirius sniggered, "I know. I figured the only way he'd buy it is if I got him to do it when he expected it."

"How'd you get him to agree?"

"May have slipped Evans' name in there somewhere." James' face fell into a look of disgust.

"Excuse me?" said Lily behind him.

"Evans!" said Sirius, feigning surprise. "Didn't see you there." he leaned back into the folds of the couch, folding his arms over his head.

"What are you doing to Snape?" she asked sternly.

"Nothing!" replied Sirius.

"Hmph. Potter, what's he planning on?"

"Prank," said James stiffly.

"James…" Sirius said, his tone warning. He shook his head slightly. "Don't."

"Black! What are you planning?" Lily demanded, brows furrowing. Sirius frowned, pretending to ponder her question.

"Why would I tell you?" he asked finally, tapping his finger against his chin.

"Because I heard my name." she smirked. "And, I'll tell your boyfriend you're planning something if you don't."

Sirius' eyes narrowed. "First of all," he said icily. "Remus isn't my boyfriend-" Lily snorted, but Sirius continued on as if he hadn't been interrupted. "And your name isn't private property. What if I'd just been telling Snape off for following you around?"

"Because he isn't, and you wouldn't." she sighed. "Fine, don't tell me. But if I find out something happened to him, I'll report you to McGonagall. You too, Potter. Don't forget, I'm a Prefect." She stalked back over to the table where she was tutoring a nervous looking fourth year in Charms. Sirius rolled his eyes.

"She has no proof." said Sirius, kicking his legs up onto the coffee table.

"Sirius…" said James. "If Remus finds out about this, he'll be seriously angry with you. Then he really might not be your boyfriend." James lowered his voice to a whisper. "You know, anymore."

"Well then, he'll just have to not find out." said Sirius silkily.

"I don't... " James looked back to the fire. "I don't like it, Sirius."

"When'd you lose your nerve, Potter?" asked Sirius, nudging James with the toe of his shoe. James glanced at him sideways.

"It's serious, Sirius, what you're planning." he sighed. "If something goes wrong, Remus could…" James trailed off, watching as Remus, himself, came slowly through the portrait hole, looking exhausted and sad. He limped slowly over to Sirius and James - he'd injured himself badly last time, having lost control to the point where Sirius and James had to take him down deep within the forest. He brightened a little at the sight of Sirius, a small smile and a flush spreading over his face.

"Hello," said Sirius, patting the couch next to him. "You look tired."

"Just got back from Madame Pomfrey." he replied. He pressed a hand against Sirius' leg as he slowly lowered himself onto the couch. Sirius threw an arm over the back of the couch, though he was careful not to wrap it too tightly around Remus, in case Lily was still looking. Remus noticed this, and frowned.

"Are you okay?" Remus asked.

"Yeah, I'm fine, why?" Sirius replied, too quickly.

"Nothing, I guess." Remus' eyebrows didn't settle from their crease, though. He shook his head and continued with his previous train of thought. "She said my leg healed too far by the time I'd been to see her." he added in a whisper: "thank you, lycanthropy!" The trio laughed slightly, and Remus continued, his voice returning to a normal level. "Well, anyway, she said I'd have a bit of pain for a little while longer, and for you three to take good care of me… when I'm back."

Sirius gave him a knowing smile, but avoided James' eyes. He could feel his best friend's gaze upon him, but tried to keep his face in a tight lipped smile.

"Well…" said Remus slowly, who obviously had expected a better reaction than the uncomfortable silence that followed, "I think I'm going to turn in early." He rose, taking his book bag with him. Remus looked at Sirius, a questioning expression on his face. Sirius shook his head a little.

"I'll… be up in a mo'." said Sirius. "Feeling tired too." Remus smiled, but it didn't quite reach his eyes. He nodded and left, limping just a little.

"Say anything," said Sirius through clenched teeth once Remus had closed the door behind him. He swung his legs off the table so he could lean forward, "and I will deny everything. I swear, James, don't ruin this for me. I would love to see the look on Snape's face when a giant dog comes bounding straight at him." James nodded, though he rolled his eyes towards the ceiling.

"Of course, Padfoot," James replied. "I solemnly swear-" he broke off, looking around. "Wait. Where's Wormtail, now I think of it?" he asked.

"Dunno," said Sirius, stretching and yawning. "You wanna help me figure out how this'll work?" James nodded, finally cracking a large grin.

* * *

Sirius didn't decide to go to bed until long after everyone, including James, had gone to the dormitories. The fire had turned to embers when he stood finally, stretching with his hands gripped tightly above his head. He heaved a great sigh - he was beginning to feel a tug of trepidation about their plan. Remus had been doing well for a few months towards the end of their fifth year, but Sirius thought between the O.W.L.'s and the absence of his friends over the summer, all of their progress form the previous year may have been lost. He wouldn't know what to do if Remus lost control again tomorrow night, especially with Snape involved.

Footsteps came echoing down the stairs, and Sirius stopped halfway to the door, noticing the leadened quality of every other footfall. The door to the boys staircase opened, and Remus, eyes bloodshot and face blotchy with tears, exited.

"I need to talk to you," said Remus, crossing his arms over his chest. Sirius frowned, stepping back. He nodded, mimicking Remus and crossing his own arms, too. "Are you going to leave me?" Remus asked after a long, pregnant pause.

"What?" asked Sirius, incredulous. His heart slowed; while he trusted James to keep quiet, he knew all too well that his feelings for Evans could have him open his mouth and blab if she were to ask him anything. "Are… are you serious?"

"Yes." said Remus. Sirius opened his mouth to speak, but Remus held up a hand to stop him. "I'm not fucking around, Sirius, and that joke is so old."

"I…" Sirius cocked his head to one side, and then shook it, like a dog trying to shake water out of its ears. "Remus, why do you think that?"

"You've barely touched me recently, and-"

"Remus," Sirius stepped towards him quickly and wrapped his arms around him. "I love you."

They stood like that in silence for what felt like a long time, Remus pressed hard against his chest, his arms still crossed, shaking silently from tears. Finally, Sirius pulled away, gripping Remus tightly by the shoulders.

"I'm serious, and I love you." This time, Remus laughed.

* * *

After many whispered discussions, some paused quickly because of Peter or Remus joining them after class, Sirius and James had a plan. James, being a stag, would wander around doing 'normal' deer things, while, all the while, keeping a watch out for Snape. Once he would see him, he'd run flat out for the Shack, ("Which could only take a couple minutes," Sirius commented, praisingly.) and give Sirius the warning call, at which point Sirius would go running down the tunnel, barking madly.

Best case scenario, Snape would scream like a little girl and wet his pants ("Hopefully not!" James said, laughing. "He'll smell like piss for weeks!"). Worst case scenario, he'd go to Dumbledore. Sirius couldn't see a downside, since Snape would be out of bounds, and hopefully, get in real trouble.

Of course, this was all dependent on Remus keeping his head. Thankfully, Peter would be there too, keeping his little rat eyes on Remus. This, Sirius thought, was a fool proof plan.

* * *

Finally, Remus left the Common Room around seven that night, loudly saying he had agreed to help Madame Pomfrey in the Hospital Wing, and to not wait up for him. He gave Sirius' shoulder a small squeeze, shot him a meaningful look, and left. Sirius' stomach twisted uncomfortably, and he, for the first time since he'd come up with this plan, felt a thread of guilt tug at his heart. James raised his eyebrows, staring at Sirius.

"You okay?" asked James slowly.

"Fine." Sirius replied shortly. "I'm fine."

* * *

At ten o'clock, James and Peter 'retired' for the night, though Sirius knew they were going up to get the Invisibility Cloak. About ten minutes later, Sirius stood, looking around the room. The toe of a shoe appeared for only a second, and Sirius made sure no one was looking as he exited through the portrait hole very slowly. Lily was still faced away, scribbling quickly at her Transfiguration homework. The Fat Lady closed behind him, and he slipped quickly under the clock, throwing the portrait a wink just before he completely disappeared.

* * *

Something had gone wrong. Remus was going crazy, slamming his body into the walls and howling so loudly that Sirius' ears were flattened against his furry head. He couldn't get Remus under control, and Peter had scurried away to warn James. Sirius didn't want to hurt remus again, but wasn't sure he had an option. Snape would be here soon; he'd seen his small dot leave the castle just before he'd transformed, leaving his robes in the tunnel, with the map stowed safely inside. He only hoped Peter would get to James quickly enough.

This had been stupid, Sirius realized. A stupid idea - a child's plan. He had no idea how to possibly get Remus under control, had never seen him act like this.

Remus' wolfish eyes found Sirius' dark ones, and though there was a certain feral quality to the yellow iris', he could see the pain that was caught there. Remus lunged at Sirius, and he yelped, falling backwards onto his haunches. He tucked his tail and bared his sharp teeth, growling viciously. Remus struck out at him again, catching Sirius in the side with one massive, clawed hand. Sirius took the opportunity as the hand made contact, and closed his jaw on Remus' arm, tasting blood; the howl that escaped Remus shot through Sirius like a physical wound, almost making him release Remus. He couldn't though. He could hear, magnified a hundred times thanks to his canine ears, hurried whispers and a shout of surprise. Remus, preoccupied by trying to wrench his hand from Sirius' grip, seemed not to notice. Footsteps, multiple pairs of them, echoed up and down the corridor, and, after what felt like ages, Sirius let Remus go. There would be a nasty scar from his teeth, he knew. He reared up as Remus went to strike him again, and set his large pause on Remus' chest, growling and barking, keeping him distracted, even as Remus tried to bite at his face with his elongated snout.

Sirius' eyes found the yellow ones again, so unlike Remus'; they were full to bursting of anger and hurt. Remus had realized what was happening. Sirius pushed against him, falling back onto all fours, and whined. He didn't know what to do. Remus sunk to all fours as well as Peter, in rat form, scurried in, racing past both of them to hide under the bed.

There was no doubt in Sirius' mind: He'd massively buggered this prank up.

* * *

Remus spent the weekend in the Hospital Wing. James came back from visiting him in the morning after their failed prank, a black and a swollen lip the only evidence of his scuffle with Snape. He shook his head when Sirius looked at him hopefully.

"Professor Dumbledore spoke to Remus early this morning. He wants to see both of us in his office after lunch." said James quietly. "And Remus doesn't want to see you, Pads." he added, very gently. He sat beside Sirius on the couch, watching him nervously. Sirius' heart fell, and his chest tightened.

"Fuck." he replied. That was all he could say.

"Really buggered this one up, didn't we?" asked James a little while later. Sirius just nodded and stared into the fire, feeling numb.

"I'm going to see him." said Sirius finally, standing up.

"Don't, Sirius," said James warningly. "He's really angry and really hurt."

"I have to make this right."

"You can't, Padfoot. Not right now, anyway. You'll just make it worse." James grabbed Sirius' wrist as he made to walk away.

"You don't know." said Sirius, yanking away. "You don't know him like I do."

"No, I don't, which is fine by me," said James with a smirk. His face fell back into a serious expression. But I know you, Pads." James looked at him beseechingly. "Please don't go. You'll say something stupid and our group will be fucked for life."

Sirius looked at James, then nodded, sinking back onto the couch. He put his head in his hands and, without caring if anyone saw, began to cry.

* * *

It was two weeks before Remus agreed to talk to Sirius alone. He'd been relatively successful at ignoring him when they would all four sit together in the few classes they still all had together or at meals, but went out of his way to avoid Sirius any time aside from that. Sirius and James had a months worth of detention with Snape, monitored closely by Professor McGonagall, which was halfway over when Sirius finally got up the nerve to ask Remus for a private word after class.

Ducking into the boys bathroom just down the hall from Professor Flitwick's classroom, Remus stood as far from Sirius as he could, arms folded over his chest. They stood there for a long time, just staring at each other. Remus' eyes filled with tears, which began to fall slowly down his face; he didn't bother to wipe them away. He just looked at Sirius, opened his mouth, closed it, then shook his head and laughed.

"You love me, is that what you've been dying to say?" Remus finally asked, voice rough with emotion. "Or, is it that you're sorry?" He shook his head again.

"Both, but you knew that." said Sirius. He watched as Remus' face turned to a grimace, and he wiped his cheeks hard with the backs of his hands.

"So why ask to talk if I already know everything you want to say?" he spat. His voice was venomous, a vindictive quality to it. "Just wanted to be sure I knew?"

"No." said Sirius. His voice was quiet now, and it was much steadier than he felt. "I just wanted a chance to really look at you, alone. I don't know when I'll be able to again, since I don't know when you'll forgive me." he paused, watching as his words registered on Remus' face. "I wouldn't even blame you if you don't. It was really stupid, and dangerous, and…" he trailed off. Remus stared at him, lips pursed as tears continued to run, waiting for him to finish. Sirius shook his head too, bits of his shaggy hair falling from its low bun. "And it went against everything I've ever promised you, Moony. And… and I've never felt like this about another person, ever. So when I say I love you, I really mean it."

Remus smirked. "It's serious, huh?" Sirius laughed, than frowned, and found that his own eyes were filling with tears now. Remus was shaking his head in small, back and forth movements, his eyes glued to Sirius, his arms glued to his chest. "I could've killed you, Sirius! You, or Peter, or James, or Severus! And I can't live with that thought. You may have fixed it in the moment this time, but what about the next time you want to play a prank on someone without telling me?" Remus' voice was growing louder, his face flushing. He wasn't crying anymore. He began to walk forward, pointing at Sirius. "You can't play games with peoples life, Sirius! That's not how the world works." He'd reached Sirius now, his finger pressed hard into Sirius' chest. "I am a monster, and there is nothing I can do about it, and I don't get to chose to transform, like you, Sirius!" He took a shaky breath. "I didn't choose this." And now, Remus was sobbing, great wracking sobs which shook him from head to foot, his shoulders bent forward. Sirius put his hands on either side of Remus' face, and when Remus didn't stop him, he pulled Remus up under his arms, throwing them over his back, and holding Remus close to him.

"Can't let you fall on the ground, Moony." said Sirius. "Bathroom's dirty." he rubbed slow circles into Remus' back with the palm of his hands. "Let's get back to the dormitory."

"We're missing class." said Remus through his tears.

"Yeah, and I have about a million more detentions, so Sprout can just tack it onto the list."

* * *

They sat in each others arms for a long time in the boys dormitory, talking and arguing and listening. Sirius did most of the listening. Remus cried, and Sirius cried, and eventually, when Sirius asked if he could kiss Remus, he nodded.

So Sirius did.

James wolf-whistled from the doorway and Peter jumped up and down clapping and Lily, who'd come up to tell Remus off for missing Arithmancy, screamed "I knew it!" and tugged the two other intruders from the dormitory. Remus laughed, looking towards the doorway, but Sirius just looked at him. He ran a hand over Remus' forehead as his hazel eyes found Sirius' steely grey ones. Lines were already beginning to form on the young face; but, Sirius noticed happily, the deepest were the ones that dug in when he smiled. He kissed him again and again and again until Remus was making a very different sound than laughter.

"Worst prank ever," Remus said breathlessly, a long time later.

"Yeah," Sirius replied. He rolled onto his side, looking at Remus, moving sweaty hair from his forehead. "I love you."

Remus smiled and pressed his forehead against Sirius' chest. "I love you, too."

* * *

 _A/N: Ahh, love. Such a great and terrible thing. I love you guys, hope you enjoyed. Keep reading. Stay safe. Don't forget to review, favorite, and follow me if you like Harry Potter fics! I've got lots of good ideas coming._

 _~B_


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